U.S. patent number 5,797,916 [Application Number 08/763,541] was granted by the patent office on 1998-08-25 for trochanteric reattachment cerclage device.
This patent grant is currently assigned to Johnson & Johnson Professional, Inc.. Invention is credited to Christopher S. McDowell.
United States Patent |
5,797,916 |
McDowell |
August 25, 1998 |
Trochanteric reattachment cerclage device
Abstract
A bone fixation device is provided that includes a retaining
member fabricated from a biocompatible material. First and second
biocompatible cables are permanently secured at one end to
respective first and second sides of the retaining member. A cable
crimp is used to bind the free portions of the first and second
cables. Cable guides on the retaining member establish an alignment
angle for the cables with respect to the longitudinal axis of the
retaining member. The retaining member can include gripping
members.
Inventors: |
McDowell; Christopher S.
(Bridgewater, MA) |
Assignee: |
Johnson & Johnson Professional,
Inc. (Raynham, MA)
|
Family
ID: |
25068114 |
Appl.
No.: |
08/763,541 |
Filed: |
December 10, 1996 |
Current U.S.
Class: |
606/74; 606/286;
606/297 |
Current CPC
Class: |
A61B
17/842 (20130101); A61B 17/74 (20130101) |
Current International
Class: |
A61B
17/84 (20060101); A61B 17/68 (20060101); A61B
17/74 (20060101); A61B 017/82 () |
Field of
Search: |
;606/69,70,71,72,74,86,103 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Buiz; Michael
Assistant Examiner: Reip; David O.
Attorney, Agent or Firm: Nutter, McClennen & Fish,
LLP
Claims
What is claimed is:
1. A bone fixation device comprising:
a retaining member fabricated from a biocompatible material, the
retaining member having a first side, a second side, and a bone
engaging face;
a first cable having a first end and a second end, the first end of
the first cable being permanently secured to the first side of the
retaining member at a first junction;
a second cable having a first end and a second end, the first end
of the second cable being permanently secured to the second side of
the retaining member at a second junction;
a first cable guide proximate the first junction and extending from
the first side of the retaining member; and
a second cable guide proximate the second junction and extending
from the second side of the retaining member.
2. The bone fixation device of claim 1, further comprising a cable
crimp adapted to bind the first cable to the second cable.
3. The bone fixation device of claim 1, wherein the retaining
member has a longitudinal axis and wherein the first cable guide
and the second cable guide align the respective first and second
cables at an angle with respect to the longitudinal axis that is
approximately 90 degrees.
4. The bone fixation device of claim 1, wherein the retaining
member has a longitudinal axis and wherein the first cable guide
and the second cable guide align the respective first and second
cables at an angle with respect to the longitudinal axis that is
less than 90 degrees.
5. The bone fixation device of claim 1, wherein the retaining
member includes:
a first securing structure for permanently securing the first cable
to the first side of the retaining member; and
a second securing structure for permanently securing the second
cable to the second side of the retaining member.
6. The bone fixation device of claim 5, wherein each of the first
and second securing structures includes a malleable tab which is
crimpable over the respective cable ends to secure the respective
cable to the retaining member.
7. The bone fixation device of claim 1, further including a
plurality of gripping members extending from the retaining
member.
8. The bone fixation device of claim 7, wherein each of the
gripping members includes a barb.
9. The bone fixation device of claim 8, wherein each barb of the
gripping members is approximately 1 mm long.
10. The bone fixation device of claim 1, further comprising a
plurality of barbs projecting from the bone engaging face of the
retaining member.
11. The bone fixation device of claim 1, wherein the bone engaging
face includes a textured portion.
12. The bone fixation device of claim 1, wherein the retaining
member includes a second face opposite the bone engaging face, the
second face and the bone engaging face defining an aperture
therebetween; and further including a bolt having a shank and an
expanded head, wherein the shank is insertable through the aperture
from the second face and wherein the expanded head engages the
second face.
13. The bone fixation device of claim 1, further comprising:
a third cable having a first end and a second end, the first end of
the third cable being permanently secured to the first side of the
retaining member; and
a fourth cable having a first end and a second end, the first end
of the fourth cable being permanently secured to the second side of
the retaining member;
wherein the bone engaging surface forms a concave surface, and
wherein the first cable is angled toward the third cable and the
second cable is angled toward the fourth cable.
14. The bone fixation device of claim 13, wherein the retaining
member includes a first end from which extend three gripping
members and a second end from which extend two gripping
members.
15. The bone fixation device of claim 14, wherein one of the
gripping members is substantially aligned with the longitudinal
axis of the retaining member.
16. The bone fixation device of claim 14, wherein at least one
gripping member has a greater amount of concave curvature than the
other gripping members.
17. A bone fixation device comprising:
a retaining member fabricated from a biocompatible material, the
retaining member having a first side, a second side, and a bone
engaging face;
a first cable having a first end and a second end, the first end of
the first cable being permanently secured to the first side of the
retaining member at a junction;
a second cable having a first end and a second end, the first end
of the second cable being permanently secured to the second side of
the retaining member at a junction;
a first cable crimp adapted to bind the first cable to the second
cable;
a first cable guide proximate the junction of the first cable and
extending from the first side of the retaining member;
a second cable guide proximate the junction of the second cable and
extending from the second side of the retaining member; and
a plurality of gripping members extending from the retaining
member.
18. A bone fixation device comprising:
a retaining member fabricated from a biocompatible material, the
retaining member having a first side, a second side, and a bone
engaging face;
a first cable having a first end and a second end, the first end of
the first cable being permanently secured to the first side of the
retaining member at a junction;
a second cable having a first end and a second end, the first end
of the second cable being permanently secured to the second side of
the retaining member at a junction;
a third cable having a first end and a second end, the first end of
the third cable being permanently secured to the first side of the
retaining member at a junction; and
a fourth cable having a first end and a second end, the first end
of the fourth cable being permanently secured to the second side of
the retaining member at a junction;
a first cable crimp adapted to bind the first cable to the second
cable;
a second cable crimp adapted to bind the third cable to the fourth
cable;
a first cable guide proximate the junction of the first cable and
the first side of the retaining member;
a second cable guide proximate the junction of the second cable and
the second side of the retaining member;
a third cable guide proximate the junction of the third cable and
the first side of the retaining member;
a fourth cable guide proximate the junction of the second cable and
the second side of the retaining member; and
a plurality of gripping members extending from the retaining
member, each of the gripping members including a barb, and one of
the gripping members being substantially aligned with the
longitudinal axis of the retaining member.
Description
CROSS-REFERENCE TO RELATED APPLICATION
--Not Applicable --
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
-- Not Applicable --
FIELD OF THE INVENTION
The present invention relates to a medical implant, and more
particularly to a bone reattachment device.
BACKGROUND OF THE INVENTION
Various orthopaedic procedures entail the use of wires and plates
to reinforce and splint bones that are fragmented due to traumatic
injury or deliberately severed during an arthroplasty procedure.
For example, during some hip arthroplasty procedures the greater
trochanter is separated from the proximal end of the femur so that
soft tissue attached to the greater trochanter can be moved aside
in preparation for implantation of a femoral stem. After the
femoral stem is seated within the medullary canal of the femur, the
greater trochanter is reattached to the proximal end of the femur.
Because the greater trochanter is subjected to considerable stress
during ambulation, mechanical reinforcement of this bone portion is
necessary.
Bone reattachment techniques can require bone screws or pins to
hold bone portions together. With respect to hip arthroplasty, a
bolt and a washer can be used to secure the greater trochanter to a
femoral stem adapted to receive the bolt. Other binding or
reinforcement devices include a structure through which wires are
threaded to bind the greater trochanter to the femur. With respect
to the wire or cerclage devices, each of several wires or cables
are independent of the structure (i.e., not attached to the
structure before the operation) and must be secured to the
structure during the surgical procedure. Use of these devices
entails tedious manipulation of the wires to correctly position
them and to attach them to the structure in situ. Not only can it
be difficult to hold the structure and the wires in a required
position while loose ends of the wire are manipulated, but it can
be inconvenient or clinically disadvantageous to perform cable
tightening and/or securing on or near the structure.
For example, U.S. Pat. No. 4,269,180 discloses a device that is
configured for reattachment of the greater trochanter to the
proximal end of the femur. However, the device shares deficiencies
with the previously discussed devices in that it has holes through
which both ends of a free wire must be threaded. Following the
threading of the wires into the body of the device, a central
portion of the device must be crimped to secure the wires.
SUMMARY OF THE INVENTION
The present invention overcomes disadvantages of known bone
reattachment or fixation devices by providing a bone fixation
device with integral cerclage cables that may be extended from the
device at a predetermined angle to ensure proper encirclement of a
bone. Because the cables and the fixation device form a unified
element, the cables can be quickly, easily and properly positioned.
Binding the free cable ends together, such as by crimping, can be
performed at selected locations away from a bone retaining
structure of the bone fixation device.
In an exemplary embodiment of the invention, a bone fixation device
includes a retaining member fabricated from a biocompatible
material. The retaining member has a first side, a second side, and
a bone engaging face. First and second cables are secured to the
first and second sides, respectively. A cable crimp can be provided
to bind the first cable to the second cable. First and second cable
guides can be provided to align the respective first and second
cables at an angle with respect to the longitudinal axis of the
retaining member. Gripping members can extend from the retaining
member; and the gripping members can include barbs to enhance
fixation to a bone surface onto which the retaining member is
placed. In addition to, or instead of barbs, the bone engaging face
of the retaining member can include a textured surface portion. The
retaining member can further include a hole through which a
fixation member is insertable.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present invention and the
attendant advantages and features thereof will be more readily
understood by reference to the following detailed description when
it is considered in conjunction with the accompanying drawings
wherein:
FIG. 1 is a perspective view of the bone fixation device in
accordance with the invention;
FIG. 1A is a view of a bolt that is suitable for engaging the bone
fixation device of FIG. 1;
FIG. 2 is a side view of the bone fixation device illustrated in
FIG. 1;
FIG. 3 depicts an alternative embodiment of the fixation
device;
FIG. 4 illustrates the fixation device secured to a femur; and
FIG. 5 illustrates an alternative embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a bone fixation device that is specifically
configured for reattachment of the greater trochanter to the
proximal end of a femur from which it has been severed. The device
includes a body portion or retaining member 10 from which extend
elongate retaining or gripping members 12 that define the periphery
of the retaining member. One or more of the gripping members 12
include spikes, points, or barbs 14 that readily penetrate the
relatively soft bone of the greater trochanter when pressure is
applied to the barbs. In addition to or instead of barbs 14 on or
near the ends of the gripping members 12, the entire bone engaging
surface 16 of the retaining member 10, or a portion thereof, can
include roughened or textured regions 18. The barbs 14 and/or
textured regions 18 engage the outer surface of the greater
trochanter to inhibit slippage or movement of the retaining member
10 with respect to the outer surface of the trochanter onto which
it is placed.
In an exemplary embodiment, the retaining member 10 includes five
elongated gripping members 12, wherein each gripping member
includes a 1 mm barb 14 at its distal end. In the embodiment
illustrated in FIG. 1, three gripping members extend from a first
end of the retaining member 10, wherein the top center gripping
member 12 is longer than the adjacent, flanking gripping members
and wherein the top center gripping member is substantially aligned
with the longitudinal axis of the retaining member. Two gripping
members 12 extend from a second end of the retaining member 10.
Other embodiments of the retaining member 10, include more or less
than five gripping members 12 and include barbs 14 that are longer
or shorter than 1 mm. The bone engaging surface 16 of the retaining
member 10 and the gripping members 12 can be shaped as required for
particular arthroplasty procedures. For embodiments of the fixation
device that include a textured region 18, the textured region can
be a grit blasted surface or an as cast macrotexture that encourage
bone ingrowth.
Referring to FIGS. 1 and 1A, an optional hole 20 through the
retaining member 10 can be provided to locate, align, and/or guide
a trochanteric bolt, screw or other fixation member 22 with respect
to the greater trochanter and/or a femoral stem. The retaining
member 10 can be fabricated from titanium alloys such as Ti-6Al-4V,
cobalt chrome (CrCo), stainless steel, or any other biocompatible
metal or metal alloy. Biocompatible plastics can also be employed.
In an illustrative embodiment, represented by FIG. 1A, the fixation
member 22 is a bolt having an expanded head 23 adapted to engage
the face opposite the bone engaging face when the bolt is inserted
through the hole from the second face. Instead of, or in addition
to the hole 20, the retaining member 10 can include a cutout region
24 and/or perforations therethrough. Not only does the cutout
region 24 reduce the weight of the device, as well as its cost, but
it also permits fibrous tissue to grow in and around the cutout to
further stabilize and secure the retaining member 10 to the
trochanter.
The retaining member 10 that is illustrated in FIG. 1 includes four
cable guides 26, 26'. Cables 28, 28' extend from each cable guide
26, 26'. Each cable 28, 28' has a fixed end and a free end, wherein
the cable guides 26, 26' establish a permanent, pre-operative
junction between the fixed end of each of the cables 28, 28' and
the retaining member 10. The cable guides 26, 26' can be oriented,
or cause the cables 28, 28' to be oriented, at a predetermined
angulation with respect to other cables or with respect to the
retaining member 10. For example, the embodiment of the bone
fixation device illustrated in FIG. 1 includes a first pair of
opposed cable guides 26 that orients the associated cables 28 at
slightly less than 90 degrees with respect to the longitudinal axis
of the retaining member 10. A second pair of opposed cable guides
26' positions the associated cables 28' at much less than 90
degrees with respect to the longitudinal axis of the retaining
member 10. Angulation of one or more of the cables 28 with respect
to the retaining member 10 allows stress to be applied to the femur
and trochanter in a direction that improves reapproximation of the
greater trochanter to the remainder of the femur. However, if
desired, the cable guides 26, 26' can align the respective cables
28, 28' at approximately 90 degrees with respect to the
longitudinal axis of the retaining member.
As used herein, "cable" is intended to encompasses any elongate
flexible member, such as a plastic band or strip, a solid wire, or
braided wires. The cable can include exposed biocompatible metal or
be covered with a biocompatible plastic. In an exemplary
embodiment, the cables are braided cobalt chrome or stainless steel
wire.
FIG. 2 is a side view of the bone fixation device shown in FIG. 1.
In this illustration, the concave curvature of the retaining member
10 and the gripping members 12 are clearly evident. In the
illustrated embodiment, the gripping members 12 that flank the top
center gripping member have an even more pronounced curvature than
the top center gripping member to allow better conformity with the
curved face of the greater trochanter. Additionally, the retaining
member 10 can have a double concave or bowl-like shape to conform
to the shape of the trochanter.
Referring now to FIG. 3, an embodiment of the bone fixation device
is shown that illustrates a securing structure for affixing a cable
30 to a retaining member 32. In this embodiment, the securing
structure includes first and second malleable tabs 34 and 36 that
extend from an angled cable guide 38. A cable 30 traverses the
retaining member 32 and passes between the tabs 34 and 36. The tabs
can be bent over the cable 30 and crimped tightly to render the
cable immovable with respect to the retaining member 32 proximate
the cable guide 38. A second cable guide 38' shown tabs in a bent
or crimped position. Other embodiments of the securing structure
include a single tab or more than two tabs.
The securing structure can include a passage through the retaining
member that includes an integral locking device or a deformable
portion of the retaining member capable of trapping a portion of a
cable therein. Alternatively, the securing structure can include a
socket in the retaining member into which one end of the cable is
bonded with heat or an adhesive material. Furthermore, a single
cable can traverse the retaining member and thus extend from
opposing cable guides; or individual cables can be associated with
each cable guide. For descriptive purposes, a single cable that
extends from two opposing cable guides can be characterized as two
cables. Many other techniques for permanently attaching a cable to
a retaining member are within the scope of knowledge of one skilled
in the art; and the technique for securing a cable to the retaining
member is not a limitation of the invention. However, the invention
does require that one or more cables be permanently attached,
pre-operatively, to the retaining member.
Comparing the embodiment of the retaining member illustrated in
FIG. 1 with the embodiment illustrated in FIG. 3, it should be
noted that whereas the embodiment of FIG. 1 includes scalloped
sides, the embodiment of FIG. 3 includes substantially straight
sides 40 and 42 which are not parallel to each other or to the
longitudinal axis "1" of the retaining member.
Referring now to FIG. 4, an embodiment of the bone fixation device
is shown in an installed configuration. A retaining member 44
conforms to the surface shape of the greater trochanter 46 and
barbs 48 penetrate the soft surface of the greater trochanter.
Cables 50 and 50' are secured to the retaining member 44 and
encircle the greater trochanter and a femoral stem 52. Cables 50
and 50' are joined by cable crimps 54 and 54' using conventional
cerclage cable tightening and crimping tools (not shown). Excess
cable is removed. FIG. 4 clearly illustrates angulation of the
cables 50 and 50' with respect to the retaining member 44. To
further ensure correct angulation of the cables 50 and 50', the
femoral stem 52 can include a flange 53 having notches 55 and 55'
that are shaped to receive and to guide cables 50 and 50',
respectively.
As used herein, "cable crimp" is intended to encompass any
structure known to those skilled in the art for joining cables and
wires. Thus, the cable crimp can include deformable elements,
clamps, screw locks, spring locks and the like. For an embodiment
of the invention wherein the cables are notched plastic strips, the
cable crimp and be a unidirectional engagement device such as the
lock on a zip tie.
Although the invention has been described with respect to
reattachment of the greater trochanter to the femur, the invention
is readily adaptable to other applications, and the shape of the
retaining member, as well as the number and position of cerclage
cables can be adapted as desired. For example, FIG. 5 illustrates a
retaining member 56 that is configured as an elongate plate. The
retaining member 56 can include a curved face 58 that is adapted
for conformal fit against a bone surface. As described with respect
to the previous embodiments, the retaining member 56 can include
one or more barbs 60 to enhance bone fixation and/or a textured
surface. Cables 62 are permanently secured to the retaining member
56 in opposing pairs and are securable to each other at a location
separated from the retaining member after the cable has encircled a
bone or implant structure. Even if the retaining member is
configured as a circle, halves (sides) of the circular member can
be provided with opposing cerclage cables. Thus, the specific shape
of the retaining member is not to be considered a limitation of the
invention.
As used herein, "side" can refers to the edge(s) of the retaining
member between the bone engaging face and the face opposite the
bone engaging face. Thus, cables can be inserted into or extend
from such a surface. However, "side" also refers to the portions of
the retaining member separated by the longitudinal axis of the
retaining member. Cables can be secured to either or both of these
sides on either the bone engaging face or the opposing face and
still be described as being secured to a side.
Although the invention has been shown and described with respect to
exemplary embodiments thereof, various other changes, omissions and
additions in form and detail thereof may be made without departing
from the spirit and scope of the invention. All references cited
herein are expressly incorporated by reference in their
entirety.
* * * * *